| 1. |
- Zhang, Nan, et al.
(författare)
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Numerical investigations and performance comparisons of a novel cross-flow hollow fiber integrated liquid desiccant dehumidification system
- 2019
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Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 182, s. 1115-1131
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Tidskriftsartikel (refereegranskat)abstract
- The heat and mass transfer process of a novel cross-flow hollow fiber integrated liquid desiccant dehumidification system is analysed numerically. Compared with other porous media or packing towers in dehumidification applications, hollow fibre membranes have significant advantages including low weight, corrosion resistant and no liquid droplet carryover. A novel air-KCOOH cross-flow dehumidification system was designed and manufactured, with 5500 hollow fibres formed into a circular module. The variations of the dehumidification effectiveness and moisture removal rates were studied numerically and validated against experimental results under the incoming air mass flow rates of 0.08-0.26kg/s and relative humidity from 55% to 75%. The dehumidification performance comparisons for the proposed system using CaCl2, LiCl and KCOOH as the desiccants have been conducted as well. The results demonstrated that under the same m*(ratio between solution mass flow rate to the air mass flow rate), the proposed system using 62% KCOOH could achieve approximately the same latent effectiveness compared with 40% CaCl2 and 32% LiCl, with the at least 3.1% sensible effectiveness increased by. Therefore, it could be concluded that the proposed system using KCOOH as desiccant could be more applicable for dehumidification purpose compared with other systems using conventional liquid desiccants.
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| 2. |
- Gu, Yaxiu, et al.
(författare)
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Techno-economic analysis of a solar photovoltaic/thermal (PV/T) concentrator for building application in Sweden using Monte Carlo method
- 2018
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 165, s. 8-24
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Tidskriftsartikel (refereegranskat)abstract
- The solar energy share in Sweden will grow up significantly in next a few decades. Such transition offers not only great opportunity but also uncertainties for the emerging solar photovoltaic/thermal (PV/T) technologies. This paper therefore aims to conduct a techno-economic evaluation of a reference solar PV/T concentrator in Sweden for building application. An analytical model is developed based on the combinations of Monte Carlo simulation techniques and multi energy-balance/financial equations, which takes into account of the integrated uncertainties and risks of various variables. In the model, 11 essential input variables, i.e. average daily solar irradiance, electrical/thermal efficiency, prices of electricity/heating, operation & management (OM) cost, PV/T capital cost, debt to equity ratio, interest rate, discount rate, and inflation rate, are considered, while the economic evaluation metrics, such as levelized cost of energy (LCOE), net present value (NPV), and payback period (PP), are primarily assessed. According to the analytical results, the mean values of LCOE, NPV and PP of the reference PV/T connector are observed at 1.27 SEK/kW h (0.127 €/kW h), 18,812.55 SEK (1881.255 €) and 10 years during its 25 years lifespan, given the project size at 10.37 m2 and capital cost at 4482–5378 SEK/m2 (448.2–537.8 €/m2). The positive NPV indicates that the investment on the selected PV/T concentrator will be profitable as the projected earnings exceeds the anticipated costs, depending on the NPV decision rule. The sensitivity analysis and the parametric study illustrate that the economic performance of the reference PV/T concentrator in Sweden is mostly proportional to solar irradiance, debt to equity ratio and heating price, but disproportionate to capital cost and discount rate. Together with additional market analysis of PV/T technologies in Sweden, it is expected that this paper could clarify the economic situation of PV/T technologies in Sweden and provide a useful model for their further investment decisions, in order to achieve sustainable and low-carbon economics, with an expanded quantitative discussion of the real economic or policy scenarios that may lead to those outcomes.
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| 3. |
- Huang, Pei, et al.
(författare)
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A Technical Review of Modeling Techniques for Urban Solar Mobility : Solar to Buildings, Vehicles,and Storage (S2BVS)
- 2020
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Ingår i: Sustainability. - : MDPI AG. - 1548-7733 .- 2071-1050. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- The deployment of solar photovoltaics (PV) and electric vehicles (EVs) is continuously increasing during urban energy transition. With the increasing deployment of energy storage, the development of the energy sharing concept and the associated advanced controls, the conventional solar mobility model (i.e., solar-to-vehicles (S2V), using solar energy in a different location) and context are becoming less compatible and limited for future scenarios. For instance, energy sharing within a building cluster enables buildings to share surplus PV power generation with other buildings of insufficient PV power generation, thereby improving the overall PV power utilization and reducing the grid power dependence. However, such energy sharing techniques are not considered in the conventional solar mobility models, which limits the potential for performance improvements. Therefore, this study conducts a systematic review of solar mobility-related studies as well as the newly developed energy concepts and techniques. Based on the review, this study extends the conventional solar mobility scope from S2V to solar-to-buildings, vehicles and storage (S2BVS). A detailed modeling of each sub-system in the S2BVS model and related advanced controls are presented, and the research gaps that need future investigation for promoting solar mobility are identified. The aim is to provide an up-to-date review of the existing studies related to solar mobility to decision makers, so as to help enhance solar power utilization, reduce buildings’ and EVs’ dependence and impacts on the power grid, as well as carbon emissions.
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| 4. |
- Wang, Yuhao, et al.
(författare)
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A novel Energy-Flow based Ensemble Calibration model for rapid and accurate energy-economic performance prediction of deep energy retrofit in single-family houses
- 2022
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 258
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Tidskriftsartikel (refereegranskat)abstract
- In Europe, 68% of residential building stocks are single-family houses, of which roughly 54% are constructed before the 1970 s with poor energy efficiency. However, few studies have addressed the issue of ‘Rapid and accurate energy-economic performance prediction of deep energy retrofit in single-family houses’ over the past decades. Recently, this issue has been discussed in limited research via Black- or White-box based building energy models to predict post-retrofit energy-economic performance. Applying the Black-box models, low accuracy occurs due to inadequate data, neglect of coupling effects in deep energy retrofit combinations and lack of complex heat transfer phenomena in single-family houses. Conversely, the White-box models with time-consuming and numerous dynamic simulations are very hard to be implemented at a building cluster or urban scale.This paper proposes a novel Energy-Flow based Ensemble Calibration model to tackle this issue, with a maximum discrepancy of 6% compared to other building performance simulation results and 0.72 s computing time on a single combination. This model consists of three layers 1) input neurons, 2) complex heat and electrical transfer models, and 3) output neurons. By replacing the layer of hidden neurons with complex heat and electrical transfer models in conventional Black-box models, the coupling effects in deep energy retrofit combinations and complex heat transfer phenomena are thoroughly considered in this research. Besides, the computational efforts are substantially reduced with only a few building performance simulations required for baseline building and identified individual retrofit measures. A semi-detached 1960 s Italian single-family house is selected as a case study to validate the calculation results from this model against real energy consumption of baseline and post-retrofit scenario, with a discrepancy of −0.66% and 1.03%, respectively.
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